Fixed: endif statement is missed in gsmL1prim.h.
diff --git a/gsmL1prim.h b/gsmL1prim.h
index f33b2e0..4da27a6 100644
--- a/gsmL1prim.h
+++ b/gsmL1prim.h
@@ -408,3 +408,5 @@
 
 enum GsmL1_PrimId_t id;
 } GsmL1_Prim_t;
+
+#endif